Wow lol I was thinking of doing a Shadow!Prussia just for the fun's (Maybe a kind of he didn't really die type of thing a mix of the normal hetalia universe and dreamtalia universe) Any ideas of how I could go about this?

oh god ... heum ... it's yours in fact , but maybe you should do some shadows places , like the original have shadow in half of his face , on his neck and arms and a bit on his leg , so maybe you should just add some shadow in your face too , but you do what you want , and if you want to add some black on your arm , i found a tutorial on how to do a kind of sleeves it's really easy , I'll add the tutorial when i will find it ^^